Explosion-preventing device



R. T. FL DODDS.

EXPLOSION PREVENTING DEVICE. APPLICATION FILED MAY I0, I920.

l,3%,879 Patented Nov. 7, 1922. I FIG]. F1612,

Patented Nov. 7, 1922. I

UNITE S'EAE'Efi Wyatt? FAJTEN FFEQE.

EXPLOSION-PREVENTING DEVICE.

Application filed May 10,

To all whom it may concern Be it. known that I. Rowxx T. F. Dooos. a citizen of the United States. residing at Stratt'ord. in the Province of Ontario. Dominion of Canada, have invented a new and useful Improvementin Explosion-Preventing Devices, of which the following is a full, clear, and exact description.

The present invention relates broadly to humidifying apparatus or devices of this nature for use in connection with working areas containing dangerous combustible mixtures.

The principal object of the present:- invention is to provide an apparatus for maintaining at all times a stable atmospheric condition in dust laden working areas.

A further object of the present invention is to provide an apparatus for maintaining predetermined minimum amounts of free water vapor in dangerous working areas.

Still a. further object of the invention is to provide an apparatus adapted to directly apply the water vapor in localized areas posseming the most dangerous atmospheric conditions, whereby explosions in such areas are prevented.

The foregoing and other objects, together with their attendant advantages. will be apparent as the invention becomes better understood by reference to the accompanying specification and drawings forming a part thereof, it being premised that changes may be made in the various details and the mannor of operation within the scope of the appended claims'without departing from the spirit of the invention.

Figure 1 is a longitudinal sectional view through an elevator or bin equipped with my invention.

Figure 2 is a similar view of a portion of a modified form of apparatus, and

Figure 3 is an enlarged sectional view through a portion of the wall structure pro vided with vci'itilating openings.

The annual loss of life and noperty re sulting from explosions in coal mines. flour and feed mills. grain ele'ators. threshing machines. separators, cork mills, and the like. has stimulated considerable activity in connection with means for preventing such explosions. Such explosions are universally attributed to the existence in the atmosphere oi amounts of dustor powder from the material being worked which is in such 1920. Serial No. 380,204.

proportion that an explosive mixture is produeed. The actual explosion of such mixtures, where the proper conditions exist, may be caused by any one of a large number of improper conditions. Heretotore etlorts to prevent such explosions have been directed toward the elimination either of the dust or powder from the atmosphere, or oi. the means responsible for the production of the explosion. These efforts have not overcome the danger inherent in. industries where these conditions exist and the present invention is directed, not toward the elimination either of the explosive material in the atmosphere, or of the means which bring about the explosion. but toward an apparatus for preventing an atmospheric condition capable of supporting the combustion or of permitting explosions.

By a large number of experiments and investigations conducted under diilerent conditions and extending over a number of years. I have found that the dust or powder present in the atmosphere possesses deliques cent properties and that. therefore, such dust. when present in sufficientquantities. in a limited supply of air, will soon absorb all of the available moisture and thereby produce an unstable atmospheric condition. As long as air contains a predetermined. minimum of water vapor, or moisture, a stable condition exists, but the elimination of such vapor produces an unstable relation between the remaining constituents of the air and explosions may be easily produced. The present invention aims to prevent the creation or existence of such an unstable relationship by maintaining at all times a, predetermined minimum of water vapor in the atmosphere by supplying additional vapor as the free vapor is absorbed by the dust.

In Figure 1 of. the drawings there is illustrated a grain bin or elevator 1, of any desired construction. These bins are frequently seventy-five to one hundred feet deep with no means provided for ventilating the interior. It is obvious, therefore, that the grain dust soon absorbs all of the available moisture. particularly in the working area adjacent the bottom of the bin. For preventing such an action there is provided a water vapor supplying device comprising a tank 2. having an inlet 3. which may be controlled by a float at or other constant level maintaining device. Extending into the tank below the water level therein is a perforated pipe 5 adapted to receive a supply of air from a blower 6. This air passing through the water will pick up a considerable amount of moisture which will in turn be conducted through the pipe 7 to the interior of the bin 1. lVithin the interior of the bin the pipe 7 may be provided with a series of openings 8, gradually increasing in diameter toward the bottom of the bin. During the initial stages of filling a bin which has been emptied. with the blower 6 in operation. it is apparent that a larger portion of the moist air will be directed directly into the working area adjacent the bottom of-the bin by reason of the large openings in the pipe 7 adjacent this point. As the level of the grain rises, it will successively cut off these openings, thereby controlling the point of application of the moist vapor.

In Figure 2 the bin 1 is illustrated as provided with a pipe '7 having a. series of openings 8 therein. each controlled by a valve 9. These valves may have a pivotal mounting 10 on the pipe 7* and be provided with a crank 11 extending outwardly therefrom and attached to a link 12. This link in turn may be controlled by a counterweighted lever 13 normally adapted to extend in horizontal position. During the filling of the bin the weight of the grain on the outer end of the lever will destroy the equilibrium thereof and cause the valve 9 to move to its open position. Thus, with this form of apparatus also. the material will control the point of application of the moist vapor.

In Figure 3 there is illustrated a section 1" of an elevator bin, or similar construction. provided with a series of angular ventilators 14- extending therethrough. In constructing a new bin these ventilators may be placed in the walls thereof at any desired point. while with bins already constructed, either of the preceding forms of apparatus may be employed.

By the term dust or powder. as employed throughout this specification and claims. there is meant any material which combined in proper quantities with air, will produce an explosive mixture. The present invention. while fparticailarly valuable in connection with grain bins and the like. is not limited in this respect as it will be apparent that the apparatus shown may be utilized in other connections.

Due to the large amount of mineral matter present in most grains, and due also to the distance through which the grain must tall in the bins. there is produced a considerable amount oi friction which friction is often responsible for the production oi" explosions.

For this reason the introduction of moist air in grainbins is highly advantageous, as the friction produced is prevented from causing any explosions.

The advantages of the present invention arise from the means for preventing the creation or existence of an atmospheric condition conducive to, explosions.

Further advantages of the invention arise from the means provided for directing the moist air directly into the working area possessingthe most dangerous characteristics.

I claim:

1. An apparatus for preventing explosions, comprising an enclosed dust laden working area, and means for supplying moisture vapor directly to the portion of said area having the most explosive properties. said point of application being controlled by the dust producing material within said area, substantially as described.

2. An apparatus for preventing explosions in grain bins, comprising a pipe. extending into said bin and provided with a series of openings. and means for supplying water vapor to said pipe during the filling of said bin. with grain, the variation in the level or! the grain in said bin automatically varying the point oiapplication of the water vapor, substantially as described.

An apparatus for prcvei'iting explosions in grain bins, comprising a pipe extendin into said bin and provided with a series or openings, means normally closing each of said openings, and means for supplying water vapor to said pipe during the filling of the bin with grain. the grain in said bin controlling the operation. of the means for closing said openings. su'bstantiallv as described. I

1-. In an apparatus for preventing explosions. an enclosed working area laden with explosive dust, and means for supplying moisture vapor to said area at a plurality oi different points. the point of application of said vapor being varied by the dust producing nraterial within said area. substantially as described.

5. In an apparatus for preventing explosions in grain bins, a pipe extending into said bin in contact with the grain therein. and means for supplying moisture vapor to said pipe. said pipe having openings in the portion thereof extending within the bin for supplying gradually increasing amounts of moisture vapor to successively different portions of said bin which are. subjected, to greatest dust concentration during the lilling operation. substantially as descril'ied. I

In testimony whereof: I have hereunto set my hand.

R-OlVAN T. F. DODDS. 

